Compact electromagnetic pulse disconnect system

ABSTRACT

Methods and systems are provided for an electromagnetic pulse disconnect assembly. In one example, an electromagnetic disconnect assembly includes an electromagnetic coil assembly including an electromagnetic coil, an armature cam including an annular ring and a plurality of bidirectional cam ramps extending in an axial direction from the annular ring, where the annular ring is adapted to have face-sharing contact with the electromagnetic coil assembly when the electromagnetic coil is energized and be spaced apart from the electromagnetic coil assembly when the electromagnetic coil is de-energized, and a cam follower a plurality of radially extending guides arranged around a circumference of the cam follower and spaced apart from one another via a plurality of elongate apertures, each of the plurality of elongate apertures adapted to receive one of the plurality of bidirectional ramps of the armature cam. The assembly may further include a latching system.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 16/206,791, entitled “COMPACT ELECTROMAGNETIC PULSE DISCONNECTSYSTEM”, filed on Nov. 30, 2018. The entire contents of the above-citedapplication is hereby incorporated by reference in their entirety forall purposes.

FIELD

The present application relates generally to a compact electromagneticpulse disconnect assembly and related systems for engaging anddisengaging two rotating components of a vehicle.

SUMMARY/BACKGROUND

Modern vehicles often incorporate one or more drivetrain modes forproviding power from an engine to the driven wheels. For example, avehicle with only a two-wheel drive system, or 4×2 mode, may providepower via one or a series of rotating shafts to two wheels of thevehicle. Vehicles such as compact cars may use a front wheel drivesystem with power provided to the two front wheels. In other, oftenlarger vehicles, it is often desirable to incorporate both two-wheeldrive and four-wheel drive driving modes, wherein power may beselectively distributed to two wheels in one mode and four wheels inanother mode. Vehicles of different sizes often incorporate two-wheeldrive of the rear wheels and four-wheel drive for the purpose ofenabling better handling during varying traction conditions while stillbeing able to switch to two-wheel drive to reduce fuel consumption andreduce wasted power.

For vehicles with switchable drive modes, devices and systems are neededfor engaging and disengaging drivetrain components such as axles andshafts. As such, disconnect assemblies are used that often involve aform of clutch that can move to connect or disconnect two rotatablecomponents such as two shafts. The disconnect assemblies can be placedin a variety of areas in the drivetrain of a vehicle, including at thewheel ends, at one or more axles, or along one of the drive shafts.Through the use of disconnect systems, vehicles can be made moreversatile by having the ability to switch between different drive modesdepending on the driving conditions and operator desire.

In some powertrain disconnecting systems, vacuum directed from thevehicle engine is used as the motive or actuating force that powers thedisconnecting systems. In particular, the disconnecting system actuatorsmay be powered by the vacuum. In many systems, the vacuum is directedvia a passage from the intake manifold of the gasoline-fueled engine.Due to this, the vacuum level, or amount of force or pressure availablefrom the vacuum, may vary as engine throttle settings change along withengine load. For many engine systems, the vacuum level (amount ofpressure available) may be limited or vary due to the effects ofaltitude. Furthermore, temperature changes can also cause pressurefluctuations in the vacuum level, thereby causing fluctuations inmovement of the disconnect actuator which may result in undesirablemovement of disconnect components such as the diaphragm and clutchcomponents. Additionally, in some vehicles vacuum may not be readilyavailable since various vehicle accessory systems may not be powered byvacuum, or the vehicle may be designed to remove engine intakeconnections such as vacuum lines in order to enhance engine control andperformance. Finally, vacuum-powered powertrain disconnect systems arebecoming less desirable with more advanced vehicle design. As such,powertrain disconnect systems are needed that are powered by sourcesother than vacuum and feature designs conducive to modern vehiclesystems.

Additionally, in other applications, such as other clutching or brakingsystems, motion may need to be retarded or produced quickly. In oneexample, electromagnetic coils may be utilized in wet plate clutches orlocking differentials. However, the components included in a disconnectsystem employing electromagnetic coils for initializing transitionsbetween clutch positions may be numerous, complex, and take upsignificant packaging space, thereby increasing a size of the entiresystem and reducing flexibility of the disconnect system (e.g., to beused in various applications. The inventors herein have recognized theabove issues and developed various approaches to address them.

Thus in one example, the above issues may be at least partiallyaddressed by an electromagnetic disconnect assembly, including: anelectromagnetic coil assembly including an electromagnetic coil arrangedwithin an annular housing of the coil assembly, where a first end of theannular housing includes a first face; an armature cam including anannular ring with an outer face and an inner face, a plurality ofbidirectional cam ramps extending in an axial direction from the innerface, where the outer face is adapted to have face-sharing contact withthe first face of the electromagnetic coil assembly when theelectromagnetic coil is energized and be spaced apart from the firstface via an air gap when the electromagnetic coil is de-energized; and acam follower including an outer annular ring and an inner annular ringcoupled together via a plurality of radially extending guides arrangedaround a circumference of the cam follower, the plurality of radiallyextending guides spaced apart from one another via a plurality ofelongate apertures, each of the plurality of elongate apertures adaptedto receive one of the plurality of bidirectional ramps of the armaturecam.

In another example, the above issues may be at least partially addressedby an electromagnetic disconnect assembly, including: an electromagneticcoil assembly; a clutch ring; and a latching system adapted to hold theclutch ring in a first, engaged position where the clutch ring connectstwo rotating components or a second, disengaged position where theclutch ring is only connected to one of the two rotating components,after energizing the electromagnetic coil assembly to move the clutchring into either the first or second position and after de-energizingthe electromagnetic coil assembly, the latching system comprising: anannular, latching ring including a first set of teeth arranged on afirst side of the latching ring and having a first profile with asingle, same-depth tooth pattern that repeats around a circumference ofthe latching ring and a second set of teeth arranged on an opposite,second side of the latching ring and having a second profile with adifferent-depth tooth pattern having two different depths that repeatsaround the circumference of the latching ring; a guiding grooves cageincluding a third set of teeth adapted to interface with the first setof teeth in a single position; and a latching grooves cage including afourth set of teeth adapted to interface with the second set of teeth intwo different locking positions.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a simplified powertrain of a vehicle in accordance with thepresent disclosure.

FIG. 2A shows a first external, assembled view of an electromagneticpulse disconcert assembly.

FIG. 2B shows a second external, assembled view of the electromagneticpulse disconcert assembly.

FIG. 3 shows an exploded view of the electromagnetic pulse disconcertassembly.

FIG. 4 shows an assembled, cross-sectional view of the electromagneticpulse disconcert assembly.

FIGS. 5A-5E show different views of a coil assembly of theelectromagnetic pulse disconcert assembly.

FIGS. 6A-6B show detailed views of an armature cam of theelectromagnetic pulse disconnect assembly.

FIG. 7 shows a detailed view of a cam follower of the electromagneticpulse disconnect assembly.

FIGS. 8A-8F show different views of an armature cam and cam followerassembly of the electromagnetic pulse disconcert assembly.

FIGS. 9A-9B show components of a latching system of the electromagneticpulse disconnect system.

FIGS. 10A-10D show different assembly views of the electromagnetic pulsedisconnect assembly in a 4×2 position.

FIGS. 11A-11D show different assembly views of the electromagnetic pulsedisconnect assembly in a 4×4 position.

FIGS. 12A-12C show different assembly views of the electromagnetic pulsedisconnect assembly in an end-of-shift position.

FIGS. 13A-B show a flow chart of a method for shifting theelectromagnetic pulse disconcert assembly between the 4×2 and 4×4positions.

FIGS. 2-12 are shown approximately to scale.

DETAILED DESCRIPTION

The following detailed description relates to systems and methods for anelectromagnetic pulse disconnect (EMPD) assembly and selectivelyconnecting rotating components of a vehicle. An example embodiment of avehicle powertrain is shown in FIG. 1, including an engine, atransmission, various axles and shafts, and wheels for providing motivepower to the vehicle. An embodiment of an EMPD assembly operated bydiscrete electrical pulses to an electromagnetic coil of the assembly isshown in FIGS. 2-12C, which may be used with the powertrain of FIG. 1.In particular, FIGS. 2A-2B show external, assembled views of the EMPDassembly, FIG. 3 shows an exploded view of the EMPD assembly, and FIG. 4shows an assembled, cross-sectional view of the EMPD assembly. The EMPDassembly includes an electromagnetic coil (shown in FIGS. 5A-5E), anarmature cam that interfaces with a cam follower (shown in FIGS. 6A-8F),and a clutch ring for selectively engaging two adjacent rotatingcomponents (e.g., such as shafts or axles). As such, the EMPD assemblymay move the clutch ring into a 4×4 position wherein the two rotatingcomponents are rotatably coupled to one another and into a 4×2 positionwherein the two rotating components are not rotatably coupled to oneanother. FIGS. 10A-12C show partially assembled, cross-sectional,sensor, and latching system views of the EMPD assembly in the differentshift positions (e.g., 4×2, end of shift, and 4×4 positions). The EMPDassembly may further include a latching system, as shown in FIGS. 9A and9B, which holds the assembly in the selected shift position withoutrequiring the electromagnetic coil to remain energized. In this way, thecoil may only be energized when moving from one shift position toanother. An example latching mechanism of the latching system is shownin FIGS. 3, 9A, 9B, 10B, 11B, and 12B. The EMPD assembly may furtherinclude a magnetic position sensor assembly for determining a shiftposition of the assembly, as shown in FIGS. 10D, 11D, and 12C. FIGS.13A-13B show a flow chart of a method for operating the EMPD assemblyaccording to commanded shift modes (e.g., positions). The EMPD assemblymay be disposed at various positions along a vehicle drivetrain (such asthe drivetrain shown in FIG. 1). For example, the EMPD assembly may bepositioned proximate a wheel end (e.g., as a wheel end disconnect)and/or positioned on a front or rear wheel axle (e.g., as a centerdisconnect). While internal components of the EMPD assembly may besubstantially the same between a center and wheel end disconnect, theouter housings (e.g., casings) of the assembly may be altered toaccommodate the specific location along the drivetrain.

Regarding terminology used throughout this detailed description, vehicleoperation where only two wheels receive power from the engine may bereferred to as two-wheel drive, or 2WD, or 4×2. The correspondingposition of the electromagnetic pulse disconnect may be referred to as a4×2 position. Alternatively, vehicle operation where all four wheelsreceive power from the engine may be referred to as four-wheel drive, or4WD, or 4×4. The corresponding position of the electromagnetic pulsedisconnect may be referred to as a 4×4 position. In other examples,four-wheel drive may be interchangeably referred to as all-wheel drive(AWD), wherein normally unpowered wheels may receive power duringcertain conditions. To accomplish shifting between 4WD and 2WD, theelectromagnetic pulse disconnect may selectively engage two rotatingcomponents. In some embodiments, the rotating components may be axles,shafts, couplers, wheel hub assemblies, or other devices used in thedrivetrain of the vehicle for transmitting rotational power.

Modern vehicles may be operated by a large variety of drivetrain systemsthat involve selectively powering different wheels according todifferent operating conditions and/or operator (i.e. driver) commands.For example, all-wheel drive vehicles may provide power to two collinearwheels during a first operating mode, and upon detection of slippage mayalso provide power to one or more of the remaining wheels. In otherexamples, a smaller vehicle, such as a passenger car, may permanentlyprovide power to only the front two wheels of the vehicle in order toincrease fuel economy (front two-wheel drive). Yet in other examples, avehicle may be configured to selectively switch between a two-wheeldrive and a four-wheel drive mode, wherein during the four-wheel drivemode all four wheels receive power. There are advantages anddisadvantages to each vehicle drivetrain, and the particular utility andanticipated function of each vehicle may aid in determining whichdrivetrain to incorporate.

FIG. 1 shows a simple diagram of a powertrain 100 of a vehicle. In thisdiagram, the body of the vehicle along with many other components areremoved for better viewing of powertrain 100. It is noted that thepowertrain includes the components seen in FIG. 1 while a drivetrain mayrefer to the components of FIG. 1 excluding the engine and transmission,described further below. According to the powertrain configuration, thevehicle of FIG. 1 may be have a selective 4WD drivetrain, wherein therear wheels are powered in a rear-wheel drive mode (or 2WD mode) and allfour wheels are powered in a 4WD mode, the 4WD drive mode different thanthe 2WD mode. Many utility vehicles such as larger trucks, all-terrainvehicles, and sports utility vehicles may incorporate rear-wheel driverather than front-wheel drive for various reasons. One reason may bethat rear-wheel drive is more conducive to load hauling or pulling, suchas towing via a trailer connected to the rear of the vehicle.

In FIG. 1, a right rear wheel 101 and left rear wheel 102 are positionedat the rear of the vehicle, that is, the end located behind an operatorof the vehicle. In this example, left, right, front, and rearorientations are given according to the perspective of the operator ofthe vehicle. Directional arrows for the front, rear, left, and rightorientations are shown in FIG. 1. Accordingly, a right front wheel 103and a left front wheel 104 are positioned at the front of the vehicle.

Power from the vehicle of FIG. 1 is generated by an internal combustionengine 110 having multiple cylinders. Engine 110 can be a fueled bygasoline or diesel according to the specific vehicle, and in the presentexample engine 110 contains six cylinders configured in a V orientation,forming a V6 engine. It is understood that engine 110 may be configuredin different orientations and contain a different number of cylinderswhile providing power in a similar fashion as seen in FIG. 1. A shaftpowered by engine 110 may be directly coupled to a transmission 115providing the necessary gearing for driving the vehicle. Transmission115 may be a manual or automatic transmission according to therequirements of the vehicle system. A rear drive shaft 131 may beconnected to transmission 115 as an output of the transmission,providing power to the rear end of the vehicle.

During the aforementioned 2WD mode of powertrain 100, wheels 101 and 102are powered via a rear axle 132. Rear axle 132 may be a singlecontinuous shaft in some embodiments, or may be split into two axles ina bi-axle configuration, wherein the axle is interposed with a reardifferential 121. In the bi-axle configuration, a first rear axle may bepositioned between the rear differential 121 and the right rear wheel101 and a second rear axle may be positioned between the reardifferential 121 and the left rear wheel 102. The rear differential isalso attached to rear drive shaft 131. The rear differential may serveseveral purposes, including allowing different relative rotationalspeeds between wheels 101 and 102 and transferring rotation (and power)from a single direction of drive shaft 131 into two perpendiculardirections of rear axle 132, as seen in FIG. 1. For example, if thevehicle is turning in the left direction, then the inboard wheel (wheel102) may rotate at a lower speed than the rotation of the outboard wheel(wheel 101). As such, rear differential 121 may allow the two wheels torotate at different speeds in order to avoid slipping between the wheelsof the vehicle and a road that the vehicle is traveling across during aturn.

For operation of the aforementioned 4WD mode, wherein the front wheelsare driven in addition to the nominally-powered rear wheels, a system isprovided to transfer power to the front of the vehicle. A transfer case140 may be positioned near the output of transmission 115, the transfercase 140 may be configured to direct a portion of power from engine 110to a front drive shaft 133. In one embodiment, the transfer case 140 mayutilize a chain to transfer a portion of power from rear drive shaft 131to front drive shaft 133. In a similar fashion to the rear drive system,for the front drive shaft 133 connects to a front differential 122. Thefront differential 122 may be substantially the same as reardifferential 121, in that the front differential 122 allows relativerotational speeds of two wheels. As such, a front axle 134, which may bedivided into two axles of a bi-axle system, may be attached todifferential 122 on one end and to their respective front left wheel 104and front right wheel 103. In this configuration, drive power from frontdrive shaft 133 may be transferred through front differential 122 and towheels 103 and 104 via front axle 134. Since transfer case 140 allowspower to be outputted to both the front and rear axles, the 4WD mode mayallow all four wheels to be powered simultaneously. Said another way,when the vehicle is in the 4WD mode, both the front wheels 103 and 104and back wheels 101 and 102 may be driven.

For switching between 4WD and 2WD in the example of FIG. 1, a system isneeded that selectively engages and disengages power input to the frontwheels. As such, a disconnect 150 may be provided inside transfer case140 positioned in-line with an output shaft of transmission 115. In thisconfiguration, disconnect 150 may also be integrally formed with orseparate from transfer case 140. Disconnects may be used in vehicleswith more than one drivetrain mode and enable engaging or disengagingbetween two separate, rotatable input components, such as wheel hubs,axles, and drive shafts. In the present example as seen in FIG. 1,disconnect 150 is positioned inside transfer case 140. In other vehiclesystems, disconnect 150 may be placed in a variety of locations,including on front axle 134 or on front drive shaft 133, effectivelydividing the shaft into two separate lengths as seen by the dasheddisconnect 150 in FIG. 1. In other examples, the disconnect 150 may bepositioned at a power transfer unit (PTU) to enable engagement anddisengagement of the PTU shaft output. Furthermore, in some embodiments,multiple disconnects may be provided, wherein each of the multipledisconnects may be fixed to a separate component of powertrain 100. Inone example, a first disconnect 150 may be placed inside transfer case140 as seen in FIG. 1, while additional disconnects may be attached tothe wheel hub of wheel 103, the wheel hub of wheel 104, and/or alongfront axle 134. In this way, the disconnects 150 may be controlledseparately or in conjunction with each other. Depending on theparticular location of the disconnect, various names are given,including wheel end disconnect and center axle disconnect. In thepresent example, disconnect 150 may selectively connect and disconnectgears inside transfer case 140 that drive the chain that powers frontdrive shaft 133. As such, disconnect 150 effectively divides transfercase 140 (and shaft 133) from the transmission 115 and rear drive shaft131 via a system of gears, control mechanisms, and other structure, asdescribed later in more detail.

During the 2WD mode when power is only provided to rear wheels 101 and102, an input command may cause disconnect 150 to disengage fixedrotation between the two lengths of shaft 133, thereby providing nopower to front axle 134 as well as wheels 103 and 104. As such, mostpower provided by engine 110 can be directed into rear drive shaft 131with a relatively smaller amount of power diverted through transfer case140 and into the length of shaft 133 connected to the disconnect. Inother words, while disengaged, front wheels 103 and 104 may rotatefreely without receiving tractive power from the engine. Also, therotation of wheels 103 and 104 along with the rotation of axle 134 andthe portion of shaft 133 disposed in front of disconnect 150 (asdirected by the arrow in FIG. 1) does not affect the rotation of therest of the drivetrain. Specifically, since disconnect 150 separates thetwo portions of shaft 133 located to the front and rear of thedisconnect, rotation of the two lengths do not affect each other becausethey are separated (disengaged). If multiple disconnects 150 areprovided, wherein one disconnect is in transfer case 140 or at shaft 133while another disconnect is at wheel 103 and yet another disconnect isat wheel 104, then front axle 134 and a portion or all of shaft 133 maycease rotating when the disconnects disengage their input components. Assuch, front differential 122 may also cease rotating while thedisconnects disengage rotation between wheels 103 and 104 and axle 134.In this way, fuel consumption may be reduced since wheels 103 and 104may rotate freely without the added rotational inertia (moment ofinertia) of axle 134 and frictional drag of differential 122.

During the 4WD mode when power is provided to all four wheels, an inputcommand may cause disconnect 150 to engage fixed rotation between thetwo lengths of shaft 133, thereby providing power to all of shaft 133 aswell as axle 134. In the current example, fixed rotation may be causedby engagement between a series of gears and/or splined shafts thatallows the shafts on either end of disconnect 150 to rotate as asubstantially single unit. During this operating mode, power from engine110 power may be diverted substantially equally (or in otherembodiments, non-equally) to wheels 101, 102, 103, and 104. It is notedthat other drive modes are possible with the addition, change, and/orremoval of components while still conforming to the scope of thisdisclosure.

Additionally, the powertrain 100 may include an electromagnetic pulse(EMPD) disconnect 160 positioned at one or more wheel ends to engage anddisengage individual wheels with a corresponding axle (e.g., front axle134 and/or rear axle 132). This type of disconnect may be referred toherein as a wheel end disconnect. The electromagnetic pulse disconnect160 may alternately be positioned on one or both of the front axle 134and the rear axle 132. Further, the electromagnetic pulse disconnect 160may be positioned on either side of the front differential 122 and/orthe rear differential 121. For example, in one embodiment, there may bea motorized disconnect 160 positioned on each side (e.g., both sides) ofthe front differential 122 on the front axle 134. Additionally, oralternatively, there may be a motorized disconnect 160 positioned oneach side (e.g., both sides) of the rear differential 121 along the rearaxle 132. In this way, the vehicle powertrain 100 may include adual-disconnecting differential system. The type of disconnectpositioned along the front or rear axles proximate to the front or reardifferentials may be referred to herein as a center disconnect. Theelectromagnetic pulse disconnect described below may be used in one ormore of the positions of the electromagnetic pulse disconnect 160 shownin FIG. 1.

As previously mentioned, some disconnects may be powered by vacuumdiverted from the engine, such as engine 110 of FIG. 1. However, theinventors herein have recognized that vacuum may not be readilyavailable or the vacuum power may undesirably fluctuate, therebyresulting in decreased disconnect control. Thus, alternate power sourcesmay be utilized that provide simpler and more compact disconnectdesigns. As such, the inventors herein have proposed an electromagneticpulse disconnect assembly that is actuated by pulsed electric power toan electromagnetic coil on the disconnect assembly. Electric power maynot require running vacuum lines throughout the vehicle, therebyincreasing the reliability of electric power over vacuum power. First, adescription of the various components of the proposed electromagneticpulse disconnect will be given, followed by a description of theoperation of the disconnect including an example control scheme.

FIGS. 2-9 show different views and aspects of an embodiment of anelectromagnetic pulse disconnect (EMPD) assembly 200. In particular,FIGS. 2A-2B show external views of the assembled EMPD assembly 200. Anexploded (e.g., disassembled) view of the EMPD assembly 200 is shown inFIG. 3 and an assembled, partial cross-section view of the EMPD assembly200 is shown in FIG. 4. FIGS. 5A-5D show different views of a coilassembly of the EMPD assembly 200 and FIGS. 6A-6B and 7 show detailedviews of an armature cam and cam follower, respectively of the EMPDassembly 200. FIGS. 8A-8F show different views of the armature cam andcam follower assembly of the EMPD assembly 200 in different shiftpositions. As explained further below, the EMPD assembly 200 isconfigured to shift into a plurality of different positions, including a4×2 (e.g., disengaged) position, end-of-shift (EOS) position, and a 4×4(e.g., engaged) position. These different positions of the EMPD assembly200 are depicted in the different views of FIGS. 10A-12C. The same partsacross FIGS. 2-12C are numbered the same and may be discussedcollectively below with reference to the different figures.

Turning first to FIGS. 2A-2B, FIG. 2A shows a side view of the assembledEMPD assembly 200 while FIG. 2B shows a top view of the assembled EMPDassembly 200. As shown in FIGS. 2A-2B, the EMPD assembly 200 includes anouter housing 202, the outer housing 202 including a base housing 204and end housing 206 coupled to one another via one or more fasteners(e.g., screws) 210. As such, the base housing 204 and end housing 206form an entirety of the outer housing 202 and fully enclose (andentirely surrounds on all sides) the internal components of the EMPD200, except for a link shaft 208. As such, external dirt and debris maynot enter inside the outer housing 202, thereby increasing thelongevity, decreasing degradation, and improving the operation of theEMPD 200. Additionally, the base housing 204 includes a connectorhousing 214 adapted to receive and surround an electrical connector forelectrically coupling the controller of the EMPD 200 (as seen in FIG. 3)to an external source, such as a vehicle controller and/or power source.The connector housing 214 is removably coupled to a remainder of thebase housing 204 via a plurality of fasteners (e.g., screws) 218. FIGS.2A-2B further show a gasket 216 on the base housing 204.

As explained further below, the EMPD assembly 200 is adapted toselectively connect and disconnect (e.g., engage and disengage) the linkshaft 208 and a drive gear (internal component of the EMPD assembly 200,not visible in FIGS. 2A-2B), the drive gear adapted to drive and connectto another rotating component, such as an axle shaft (e.g., half shaft)or other rotating shaft coupleable to a vehicle component, such as adrive wheel. The shaft that is adapted to be connected to and driven bythe drive gear is sealed against the end housing 206 via a shaft seal212, such that no debris may enter the outer housing 202, while stillallowing the shaft to rotate.

FIG. 3 shows an exploded view 300 of the EMPD assembly 200 while FIG. 4shows an assembled, cross-sectional view 400 of the EMPD assembly 200,both FIGS. 3 and 4 showing all the internal components of the EMPDassembly 200 contained within an interior of the outer housing 202discussed above with reference to FIGS. 2A-2B. FIGS. 3 and 4 again showthe base housing 204, end housing 206, and fasteners 210 for couplingthe base housing 204 to the end housing 206. As shown in FIG. 3, thebase housing 204 includes a first plurality of apertures 302 and the endhousing 206 includes a second plurality of apertures 304 for receivingthe fasteners 210. The first plurality of apertures 302 and secondplurality of apertures 304 are arranged in respective flanges of thebase housing 204 and end housing 206, where the flanges haveface-sharing contact with one another when the outer housing 202 isassembled (e.g., the base housing 204 is coupled to the end housing206). Also shown in FIG. 3, is the connector housing 214 which couplesto an outer mounting face 306 and receiving cavity 308 arranged on oneside of the base housing 204. The receiving cavity 308 extends throughan entirety of a thickness of the base housing 204 so that an electricalconnector inserted through the connector housing 214 may provide powerto a controller 310 of the EMPD assembly 200. The controller 310 isadapted to be coupled to a side of a latching grooves cage 312 whichfits within the base housing 204 when the EMPD assembly 200 is assembled(as shown in FIG. 4). Thus, the controller 310 may be arranged on a sameside of the assembly as and aligned (along at least a portion of thecontroller 310) with the receiving cavity 308 and connector housing 214,as shown in FIG. 4.

As shown on a left side of the EMPD assembly 200 in FIGS. 3 and 4,another shaft seal 314 is arranged at a base housing end of the EMPDassembly 200 in order to seal the link shaft 208 within the base housing204. The EMPD assembly 200 further includes a retaining ring 316, a ballbearing 318, and a spacer 320. The spacer 320 is arranged adjacent to anelectromagnetic coil assembly 322, as shown in FIG. 4. The spacer 320includes an axially extending annular portion 324 which mates with andfits into an annular slot (shown in FIG. 5A and discussed further below)depressed into an outer face of the electromagnetic coil assembly 322.An opposite end of the spacer 320 (opposite to the annular portion 324),which flares radially outward relative to a central axis 350 of the EMPDassembly 200 (as seen in FIG. 4), interfaces with the base housing 204.Specifically, grooves 319 arranged around a circumference of the spacer320 are shaped to fit over corresponding extensions 321 on an interiorsurface of the base housing 204, allowing the spacer 320, and thus theelectromagnetic coil assembly 322, to translate axially, in a directionof the central axis 350, but not rotate about the central axis 350.

The EMPD assembly 200 further includes a washer 326 and armature cam328. The armature cam 328 includes an annular ring 332 with an outerface (facing the base housing end of the assembly) and an inner face(facing the end housing end of the assembly) and a plurality ofbidirectional cam ramps 330 extending in an axial direction from theinner face (shown in FIG. 3). The outer face of the annular ring 332 isadapted to have face-sharing contact with a first face 323 of theelectromagnetic coil assembly 322, which includes a friction material onthe first face 323 (in the form of a friction disk, as explained furtherbelow), when the electromagnetic coil is energized and be spaced apartfrom the first face 323 via an air gap when the electromagnetic coil isde-energized (as shown in FIGS. 8A-8F, described further below). Thebidirectional cam ramps 330 interface with a cam follower 334.Specifically, the cam follower 334 includes a plurality of elongateapertures 336 adapted to receive the plurality of bidirectional camramps 330, the elongate apertures 336 separated by a plurality ofradially extending guides 338 of the cam follower 334.

As shown in FIG. 3, on either side of the cam follower 334 is aretaining ring 340 and shift spring 342. The shift spring 342 isarranged adjacent to a washer 344. The EMPD assembly 200 furtherincludes a clutch ring 346. The clutch ring 346 is adapted to translateaxially, along the central axis 350, responsive to axial movement of thecam follower 334, as explained further below. The clutch ring 346includes an inner surface (relative to the central axis 350) including afirst set of teeth 347 separated, in the axial direction, from a secondset of teeth 348 via a space 349 (the space having no teeth). The firstset of teeth 347 is adapted to interface (e.g., mate) with correspondingteeth 354 on the link shaft 208 in both the disengaged (4×2) positionand the engaged (4×4) position of the assembly while the first set ofteeth 347 additionally interface with corresponding first teeth 356 ofthe drive gear 358 in the engaged position. Additionally, in the engagedposition, the second set of teeth 348 is adapted to interface (e.g.,mate) with corresponding second teeth 357 on the drive gear 358. Thedrive gear 358 is adapted to connect to and drive another rotatingcomponent, such as an axle half shaft or shaft coupled to a drive wheelof a vehicle. In this way, by axially moving the clutch ring 346, theclutch ring may selectively connect and disconnect the link shaft 208and the driver gear 358. For example, when the first set of teeth 347 ofthe clutch ring 346 is connected to the teeth 354 on the link shaft 208and the first teeth 356 on the drive gear and the second set of teeth348 is connected to the second teeth 357 on the drive gear 358,rotational motion may be transferred between the link shaft 208 anddrive gear 358 (for example, an axle rotationally coupled with the linkshaft 208 may drive a drive wheel rotationally coupled with the drivegear 358). FIG. 4 shows the disengaged (4×2) position of the clutch ring346.

A clutch ring cage 352 is adapted to house (and thus contain within itsinterior) the cam follower 334, shift spring 342, washer 344, and clutchring 346 (as shown in the assembled view of FIG. 4). A washer 360 fitsaround a smaller-diameter end 351 of the clutch ring cage 352 (as shownin FIG. 4). An inner shift fork 362 also fits around thesmaller-diameter end 351 of the clutch ring cage 352, adjacent to thewasher 360 (as seen in FIG. 4). The inner shift fork 362 includes aplurality of axial extensions 361, where one or more of the axialextensions 361 holds a corresponding magnet assembly 364, the magnetassembly including a magnet sled holding a magnet detectable via asensor on the controller 310 in order to detect a position of the EMPDassembly 200 (e.g., 4×2, 4×4, or EOS, as explained further below). Theaxial extensions 361 extend over a larger-diameter end of the clutchring cage 352. An outer shift fork 366 mates with the inner shift fork362. For example, as shown in FIG. 4, a portion of the inner shift fork362 extends over and surrounds at least a portion of the outer shiftfork 366. The outer shift fork 366 holds a latching ring 368. As shownin FIG. 4, the latching ring 368 is arranged outside of, relative to thecentral axis 350, and surrounds a portion of the outer shift fork 366.The inner shift fork 362, outer shift fork 366, and latching ring 368may move, axially, together with the clutch ring 346 and clutch ringcage 352.

As explained further below, the latching ring 368 is part of a latchingsystem adapted to hold the clutch ring 346 in an engaged (4×4) position,where the clutch ring 346 is coupled to both the link shaft 208 and thedrive gear 358, or a disengaged (4×2) position, where the clutch ring346 is only coupled to the link shaft (and not the drive gear), afterenergizing the electromagnetic coil assembly to move the clutch ringinto either the engaged or disengaged positions and after de-energizingthe electromagnetic coil assembly. The latching ring 368 includes afirst set of teeth 370 arranged on a first side of the latching ring 368and having a first profile with a single, same-depth tooth pattern thatrepeats around a circumference of the latching ring 368 and a second setof teeth 372 arranged on an opposite, second side of the latching ring368 and having a second profile with a different-depth tooth patternhaving two different depth grooves that repeats around the circumferenceof the latching ring 368. The latching system further includes a guidinggrooves cage 374 including a third set of teeth 376 adapted to interfacewith the first set of teeth 370 in a single position and the latchinggrooves cage 312 which includes a fourth set of teeth 378 adapted tointerface with the second set of teeth 372 in two different lockingpositions. The guiding grooves cage 374 and latching grooves cage 312couple to one another via a plurality of grooves, spaced apart from oneanother around a circumference of the guiding grooves cage 374, and aplurality of axially extending tabs, spaced apart from one anotheraround a circumference of the latching grooves cage 374 (as shown inFIGS. 3 and 4, and described further below with reference to FIGS. 9Aand 9B). The latching grooves cage 312 may be axially and rotationallyfixed to the base housing 204 via one or more fixing elements 311 on thelatching grooves cage 312 and mating fixing elements on an interior ofthe base housing 204. Additionally, the guiding grooves cage 374 isfixed to the latching grooves cage 312, and thus is also fixed in theaxial and rotational directions (around the central axis 350). However,the latching ring 368 is free to move axially between the respectiveteeth of the guiding grooves cage 374 and latching grooves cage 312 andfree to rotate around the central axis 350, as the assembly is shiftedinto the different positions, as described further below.

The EMPD assembly 200 further includes another retaining ring 380, aball bearing 382, a cushion 384, a return spring 386, a roller bearing388, another ball bearing 390, additional retaining rings 392 and 394,and the shaft seal 212. The cushion 384 may be made of a noise dampeningmaterial (such as a polymer) and thus, may be adapted to dampen thenoise of the clutch ring 346 engaging with the drive gear 358. Forexample, the clutch ring 346 may move axially, in the direction of thecentral axis, toward the drive gear 358 (when moving from the disengagedto engaged position) with increased force that may result in noise whenthe clutch ring hits the drive gear. However, the cushion 384 reducesthe noise of teeth of the clutch ring 346 engaging with the teeth of thedrive gear 358. As shown in FIG. 4, the cushion 384 is arranged adjacentto the second teeth 357 of the drive gear 358. Thus, this positioningmay prevent the clutch ring from impacting a side wall of the drive gear358.

Now turning to FIGS. 5A-5E, more detailed views of the electromagneticcoil assembly (also referred to herein as the coil assembly) 322 areshown. Specifically, FIG. 5A shows a first end view of the coil assembly322, FIG. 5B shows a first side view of the coil assembly 322, FIG. 5Cshows a second end view of the coil assembly 322, FIG. 5D shows across-sectional side view of the coil assembly 322, and FIG. 5E shows atop view of the coil assembly 322.

The coil assembly 322 includes an annular housing 500 housing anelectromagnetic coil 502 and a coil holder 504 adapted to hold fourseparate coils (e.g., coil springs) 506. The annular housing 500includes a first end 508 (shown in FIG. 5C) and second end 510 (shown inFIG. 5A), where the coil holder 504 is arranged at and across a portionof the second end 510. Legs 512 of the coil holder 504 extend across atop and bottom of the annular housing 500, from the second end 510 andtoward the first end 508. As shown in FIGS. 5A and 5C, there are fourlegs 512, each housing one of the coils 506. Each coil (e.g., coilspring) 506 is fastened to a corresponding leg 512 via a rivet 514(e.g., via soldering, in one embodiment). A portion of the legs 512 areelectrically coupled to the internal electromagnetic coil 502 via arespective electrical conductor (e.g., a copper circuit, in oneembodiment) 516. In one embodiment, only two of the coils 506 (of onlytwo of the legs) are connected to an electrical conductor 516. Forexample, as shown in FIG. 5E, only the top two coils (e.g., the coilsarranged at the top, or one side, of the coil holder 504), includingfirst coil 530 and second coil 532, include an electrical conductor 516in contact with the coils within the corresponding legs 512 while theother two coils (bottom coils, including third coil 534 and fourth coil536) are not directly coupled to an electrical conductor and thus arenot electrically coupled to the internal coil 502.

In this way, the top two coils 530 and 532, coupled to the electricalconductors 516, serve as electrical terminals of the coil assembly 322.In one example, the top two legs shown in FIG. 5E may be referred to asthe contact assembly of the coil assembly 322, where the contactassembly is adapted to be electrically coupled with the controller(e.g., controller 310 shown in FIGS. 3 and 4). As such, each of the coil530 and 532 within the top two legs is electrically coupled to theelectromagnetic coil 502 and a corresponding controller terminal of thecontroller. For example, the coil 530 within a first of the top two legsmay be the positive electrical connection to the electromagnetic coil502 and the coil 532 within a second of the top two legs may be theelectrical ground of the electromagnetic coil 502. Said another way, acontroller terminal mates with and directly connects to each of thecoils of the top two legs. In one example, the controller terminals maybe electrically coupled to each of coils 530 and 532 through therespective rivets 514 directly coupled to the coils. As a result, thecontroller may send electrical impulses, through controller terminals,to the first and second coils 530 and 532, to electrically energize andde-energize the electromagnetic coil 502.

Together, all four of the coils 530, 532, 534, and 536 of the three fourlegs serve as coil return springs of the coil assembly 322. For example,as described further below, upon energizing the electromagnetic coil502, the coil assembly 322 may translate axially toward and into contactwith the metal armature cam (due to the magnetic attraction cause byenergizing the coil 502). However, upon de-energization of theelectromagnetic coil 502, the spring force of the compressed coils 530,532, 534, and 536 may push the coil assembly 322 backwards, in the axialdirection, and away from the armature cam. The four individual coils 506of the four individual legs 512 provide a balanced return force to thecoil assembly 322 due to the distribution of the legs 512 around acircumference of the coil assembly 322. For example, while the top twolegs provide electrical connections and spring return forces, the bottomtwo legs provide additional spring forces to balance the force of thecoils in the top two legs. In this way, the four legs shown in FIGS.5A-5E provide both a return spring force and electrical connection tothe coil assembly 322. Specifically, the top two legs includes coils 530and 532 integrate both the coil electrical connections (e.g., terminals)and coil return springs into one part. While four legs are shown inFIGS. 5A-5E, in alternate embodiments, the coil assembly 322 may includemore or less non-electrically coupled legs for balancing of the coilreturn spring force.

As shown in FIGS. 5C and 5D, the first end 508 of the annular housing500 includes a first face having a friction disk 518. The friction disk518 is annular and includes a friction material arranged therein. Thefriction disk 518 is adapted to have face-sharing contact with the outerface of the armature cam when the electromagnetic coil is energized, asdiscussed further below with reference to FIGS. 8A-8F. The second end510 of the annular housing 500 has a second face arranged opposite tothe first face, the second face having an annular slot 520 depressedinward into the second face. As shown in FIG. 5A, the annular slot 520further includes a plurality of spaced apart radial extensions of theslot. As discussed above, the annular slot 520 is shaped to receive andcouple to the axially extending annular portion 324 of the spacer 320.Additionally, as shown in FIG. 5D, the annular housing 500 includes aniron core 522 and the electromagnetic coil 502 arranged within the ironcore 522. The electromagnetic coil 502 (and not coils 506) create amagnetic field for creating the magnetic attraction between the armaturecam and electromagnetic coil assembly.

Turning to FIGS. 6A-6B, detailed views of the armature cam 328 areshown. Specifically, FIG. 6A shows an isometric view of a first side ofthe armature cam 328 and FIG. 6B shows an isometric view of a secondside of the armature cam 328. As introduced above with reference to FIG.3, the armature cam 328 includes an annular ring 332 with a first (alsoreferred to herein as outer) face 602 and a second (also referred toherein as inner) face 604 and a plurality of bidirectional cam ramps 330extending outward, in an axial direction (relative to central axis 350)from the second face 604. The first face 602 and second face 604 areplanar and arranged parallel to one another and normal to the centralaxis 350. The annular ring 332 has an inner diameter 606, an overallthickness 608, and outermost diameter 610. The first face 602 is adaptedto have face-sharing contact with the planar, friction disk 518 of thecoil assembly 322, as described further below, when the electromagneticcoil is energized.

As shown in FIGS. 6A-6B, there are three bidirectional cam ramps 330spaced apart from one another around a circumference of the armature cam328. Each bidirectional camp ramp 330 is connected to an adjacentbidirectional camp ramp 330 via a connecting platform 612. However,adjacent bidirectional cam ramps 330 are not directly coupled to oneanother (e.g., a connecting platform 612 separates adjacentbidirectional cam ramps 330 from one another). Each connecting platform612 is directly coupled to the second face 604 and includes an aperture614 arranged through a center portion of the platform 612. In oneexample, the connecting platforms 612 are integrated together, as onepiece, with the annular ring 332. In another example, the connectingplatforms 612 are welded to the annular ring 332 or fastened to theannular ring 332 via the apertures 614. Each connecting platform 612spans radially across a width of the second face 604 (from the innerdiameter to an innermost outer diameter 616) and has a length (e.g., arclength) 624, in a circumferential direction around a circumference ofthe annular ring 332, each length 624 smaller than a length (e.g., arclength) 626 separating adjacent connecting platforms 612. Eachbidirectional cam ramp 330 includes a first ramp 618 and a second ramp620 that meet at an apex 622, the apex 622 positioned away from theinner face of the annular ring of the armature cam and being anoutermost extending portion of the bidirectional camp ramp. The firstramp 618 extends outward from a first connecting platform to the apex622 and the second ramp 620 extends outward from a different, secondconnecting platform to the apex 622, the first and second connectingplatforms spaced apart from one another.

FIG. 7 shows a detailed view of the cam follower 334. As introducedabove with reference to FIG. 3, the cam follower 334 includes aplurality of elongate apertures 336 adapted to receive the plurality ofbidirectional cam ramps 330, the elongate apertures 336 separated by aplurality of radially extending guides 338 of the cam follower. As shownin FIG. 7, the cam follower 334 includes an outer annular ring 702 andan inner annular ring 704 coupled together via the radially extendingguides 338. Specifically, each of the radially extending guides 338extend in a radial direction (perpendicular to the central axis 350)between the outer annular ring 702 and the inner annular ring 704. Theradially extending guides 338 are arranged around a circumference of thecam follower 334 and spaced apart from one another via the elongateapertures 336. The elongate apertures 336 extend through an entirethickness (in the axial direction) of the cam follower 334. As shown inFIG. 7, there are three radially extending guides 338 and three elongateapertures 336 which match the number (3) of bidirectional ramps of thearmature cam 328. A length (e.g., arc length) 706 of each of theplurality of elongate apertures, in a direction of a circumference ofthe inner and outer annular rings, is longer than a length 708 of eachof the plurality of radially extending guides, in the direction of thecircumference of the inner and outer annular rings. An interface betweeneach elongate aperture 336 and adjacent guide 338 includes a depressedsidewall portion 714 that angles into the elongate aperture from theguide, the depressed sidewall portion adapted to receive and interfacewith an apex 622 of the armature cam 328 (e.g., when the assembly isshifted to the 4×4 position).

Additionally, the inner annular ring 704 includes a plurality of teeth710 arranged around a circumference of an inner surface of the innerannular ring 704 which may mate with the teeth 354 of the link shaft208. Thus, the cam follower 334 may rotate along with rotation of thelink shaft 208. The outer annular ring 702 includes a plurality ofradial protrusions 712 extending radially outward, relative to thecentral axis 350, from the outer annular ring 702 and which are spacedapart from one another around the circumference of the outer annularring 702.

The EMPD assembly 200 described herein may adjust the clutch ring 346into a 4×4 (e.g., engaged) position wherein two rotating components(e.g., axles or shafts of a vehicle powertrain) are rotationally coupledto one another and into a 4×2 (e.g., disengaged) position wherein tworotating components are not rotationally coupled to one another. Thefirst rotating component may be the link shaft 208, which may berotationally coupled to another axle or shaft of a vehicle (or anothercomponent) and the second rotating component may be the drive gear 358which may be rotationally coupled (and drive) another axle or shaft ofthe vehicle.

FIGS. 8A-8F show assembled end and top views of a coil and cam assembly800 of the EMPD assembly 200 in different positions including the 4×2(e.g., retracted) position, the 4×4 (e.g., partially extended) position,and the end-of-shift (also referred to as end-of-travel), EOS, (e.g.,fully extended) position. The coil and cam assembly 800 includeselectromagnetic coil assembly 322, cam follower 334, and armature cam328. More specifically, FIG. 8A shows a first end view 802 of a coil andcam assembly 800 of the EMPD assembly 200 in a retracted position(clutch ring is in 4×2 position), FIG. 8B shows a second end view 806 ofthe coil and cam assembly 800 in a partially extended position (clutchring is in 4×4 position), FIG. 8C shows a third end view 810 of the coiland cam assembly 800 in a fully extended position (clutch ring is in theEOS position), FIG. 8D shows a first top view 804 of the coil and camassembly 800 in the retracted position, FIG. 8E shows a second top view808 of the coil and cam assembly 800 in the partially extended position,and FIG. 8F shows a third top view 812 of the coil and cam assembly 800in the fully extended position. Additionally, FIGS. 10A and 11A show anexternal view of the clutch ring 346 in the 4×2 and 4×4 positions,respectively and FIGS. 10C, 11C, and 12A show cross-sectional views ofthe EMPD assembly 200 in the 4×2, 4×4, and EOS positions, respectively.The description that follows regarding the shifting of the EMPD assembly200 may refer to each of FIGS. 8A-8F, 10A, 10C, 11A, 11C, and 12A.Components of the EMPD assembly 200 shown in FIGS. 8A-8F, 10A, 10C, 11A,11C, and 12A may be the same as components shown in FIGS. 2-7, asdescribed above. As such, these components are similarly numbered andmay not be re-introduced below with reference to FIGS. 8A-8F. Thecentral axis 350 is shown for reference (it extends into the page, asshown by the X, in FIGS. 8A-8C). In one embodiment, the 4×2 and 4×4positions may correspond to shifting modes of the vehicle, wherein ashift command may be sent to a vehicle controller, which may in turn besent to the disconnect controller 310 in order to actuate EMPD assembly200 accordingly. For example, during operation, the controller 310 maysend electrical actuation signals to the electromagnetic coil assembly322 in order to energize and de-energize the electromagnetic coil 502within the electromagnetic coil assembly 322. In response to thesesignals, the coil and cam assembly 800 may move as discussed furtherbelow with reference to FIGS. 8A-8F, 10A, 10C, 11A, 11C, and 12A.

As seen in FIGS. 8A and 8D, the coil and cam assembly 800 is in theretracted position, which may correspond to the clutch ring and EMPDassembly 200 being in the 4×2 position. As shown in FIGS. 10A and 10C,in the 4×2 position, the clutch ring 346 is only engaged with onerotating component (e.g., the link shaft 208) while another rotatingcomponent (e.g., the drive gear 358 which may be coupled to another axleor shaft of the vehicle) is allowed to rotate independently. As shown inFIG. 8D, in the 4×2 position, the coil assembly 322 and the armature cam328 are separated from one another by an air gap 814. Additionally, eachbidirectional cam ramp 330 is extending through a corresponding one ofthe elongate apertures 336 and each radially extending guide 338 ispositioned against (e.g., in face-sharing contact with) a correspondingone of the connecting platforms 612 (as shown in FIGS. 8D and 10C). Assuch, the cam follower 334 is positioned against the armature cam 328,and thus, is in the retracted position. Since the cam follower 334 iscoupled to the link shaft 208 (via teeth 710), the cam follower rotatesalong with the link shaft 208. Additionally, the armature cam 328rotates along with the cam follower 334 due to the interfacing elongateapertures 336 and bidirectional ramps 330. As seen in FIG. 8A, the apex622 of each bidirectional ramp 330 is approximately centered between twoadjacent radially extending guides 338.

When a shift from the 4×2 to the 4×4 mode is commanded, the vehiclecontroller provides electric current to the electromagnetic coil of theelectromagnetic coil assembly 322 via the spring coils coupled to theelectrical conductors, as described above with reference to FIGS. 5A-5E,in order to energize the electromagnetic coil 502 of the coil assembly322. According to the properties of electromagnetism, energizing theelectromagnetic coil 502 may create a magnetic field surrounding thecoil. As such, the coil assembly 322 is attracted to the armature cam328, which is composed of a suitable metallic material for interactionwith the magnetic field produced by the coil assembly 322. While thecoil assembly 322 is fixed from rotating, armature cam 328 rotates withthe cam follower 334, as described above. Since the coil assembly 322 isfree to translate a limited amount, in the axial direction (alongcentral axis 350), the coil assembly 322 moves, in the positive axialdirection 820 (shown in FIG. 8E), toward and into contact with theannular ring 332 of the armature cam 328 while the armature cam 328remains stationary in the axial direction. This movement of the coilassembly 322 to the armature cam 328 effectively closes the air gap 814and thereby creates friction between the coil assembly 322 and the firstface 602 of the annular ring 332 of the armature cam 328. The frictiondisk 518 on the coil assembly 322 increases this friction between thecoil assembly 322 and the annular ring 332 and reduces wear. In responseto the coil assembly 322 contacting the armature cam 328, rotation ofthe armature cam 328 may be slowed or stopped. When the armature cam 328is rotating slower than the cam follower 334, the bidirectional ramps330 of the armature cam 328 produce a force against the radiallyextending guides 338 of the cam follower 334. As a result, as shown inFIGS. 8B and 8E, the radially extending guides 338 of the cam follower334 slide partially along the bidirectional ramps 330 of the armaturecam 328, away from the connecting platforms 612 (e.g., the connectingplatforms are visible in FIG. 8B whereas they were covered by the guidesin FIG. 8A) and toward the apexes 622 of the bidirectional ramps 330.This causes the cam follower 334 to move away from the annular ring 332of the armature cam 328 (while the armature cam 328 remains stationaryis the axial direction), in the positive axial direction 820. Axialmovement of the cam follower 334, in the positive axial direction 820,causes axial movement of the clutch ring 346 (in the same direction) viashift spring 342. In this way, the actuation force provided by theenergized coil of the coil assembly 322 and armature cam 328 may forcethe clutch ring 346 in the positive axial direction 820 and intoengagement with the drive gear 358, as shown in FIGS. 11A and 11C, and asecond rotating component coupled with the drive gear. The axial motionof the cam follower 334 subsequently acts on the clutch ring 346 toproduce a shift from the disengaged to the engaged position, therebyshifting from the 4×2 to the 4×4 position. As shown in FIGS. 8B and 8E,when the coil and cam assembly 800 is in the partially extended positionthe cam follower is part way, in the axial direction, from the annularring 332 of the armature cam 328. In this position shown in FIGS. 8B and8E, the apexes 622 are arranged partway between adjacent radiallyextending guides 338. However, when shifting between the 4×2 and 4×4positions, the assembly is first shifted from the current position tothe EOS position and then the assembly settles into the desired positionafter the coil is de-energized. As shown in FIGS. 8C, 8F, and 12A, inthe EOS position, the cam follower 334 is in the fully extended positionso that it is the farthest away as possible from the annular ring 332 ofthe armature cam 328. In this EOS position, the clutch ring 346 isshifted past, in the axial direction, the 4×4 position (as seen in FIG.12A).

As described above and further below with reference to FIGS. 9A-9B, theEMPD assembly 200 includes a latching system 900 for holding the clutchring 346 of the EMPD assembly 200 in the 4×4 position without requiringthe coil of the coil assembly 322 to stay energized. For example, it isadvantageous to only energize the coil when shifting from one positionto another. However, if the latching system is not included in the EMPDassembly 200, de-energizing the coil of the coil assembly 322 wouldresult in the armature cam 328 being free to rotate along with the camfollower 334 and the return spring 386 then returns the clutch ring 346to the 4×2 position (by translating the clutch ring 346 in the negativeaxial direction). Instead, when the 4×4 position in commanded, the coilof the coil assembly 322 is energized and the clutch ring 346 is shiftedinto the 4×4 position, as described above. In addition to this motion,the latching system 900 holds the EMPD assembly 200 in the 4×4 position,even after the coil of the coil assembly 322 is de-energized. In thisstate, the vehicle will stay in the 4×4 mode until the 4×2 mode isselected.

When a shift from the 4×4 to the 4×2 mode is commanded, the controller310 again provides electric current to the electromagnetic coil 502 ofthe coil assembly, as described above, in order to energize the coil502. As a result, the guides 338 of the cam follower 334 travel furtherup the bidirectional ramps 330 of the armature cam 328 until thesidewall portions 714 of the guides 338 come into contact with theapexes 622 of the bidirectional ramps 330. As explained above, thisposition is referred to as the EOS position and is shown in FIGS. 8C,8F, and 12A. The additional travel distance causes the latching systemto switch positions, as described further below with reference to FIGS.9, 10B, 11B, and 12B. Once the latching system has switched positions,the coil of the coil assembly 322 may be de-energized. When the coil isde-energized from the EOS position, the coil assembly 322 moves awayfrom the armature cam 328 and the air gap 814 is again present betweenthe coil assembly 322 and the armature cam 328. The armature cam 328 andcam follower 334 are then free to rotate along with the link shaft 208and the return spring 386 returns the clutch ring 346 to the 4×2position. The vehicle drive mode may cycle between the 4×2 and 4×4position, stopping first in the EOS position, every time theelectromagnetic coil of the coil assembly 322 is energized for a briefduration or pulsed.

As described above, the latching system holds the EMPD assembly 200 inthe selected shift position without requiring the electromagnetic coilto remain energized. In this way, the electromagnetic coil may only beenergized when moving from one shift position to another. The latchingsystem 900 employed in the EMPD assembly 200 is shown in more detail inFIGS. 9A and 9B. Specifically, FIGS. 9A-9B show components of thelatching system 900 of the EMPD assembly 200, including the latchinggrooves cage 312 and the guiding grooves cage 374 shown in FIG. 9A andthe latching ring 368 shown in FIG. 9B. As explained above and as shownin FIG. 9B, the latching ring 368 includes the first set of teeth 370arranged on a first side of the latching ring and having a first profilewith a single depth 902 that is the same for each tooth and that repeatsaround a circumference of the latching ring 368. In this way, the singletooth profile with depth 902 repeats continuously around the entirecircumference of the latching ring 368 to make up the first set of teeth370. The latching ring 368 includes the second set of teeth 372 arrangedon an opposite, second side of the latching ring 368, the second set ofteeth 372 and having a second profile with a different-depth toothpattern having two different depths that repeats around thecircumference of the latching ring 368. For example, as shown in FIG.9B, the second set of teeth 372 are formed by repeating teeth (repeatedcontinuously around an entire circumference of the latching ring) havinga longer, first depth 904 and a shorter, second depth 906. Each tooth ofthe second set of teeth 372 is formed by two higher peaks 908 and 910arranged adjacent to one another and two deeper grooves 912 on eitherside of the peaks 908 and 910. The two peaks 908 and 910 are separatedfrom one another by a shallower groove 914. The first set of teeth andsecond set of teeth are separated from one another, on opposite sides ofthe latching ring relative to the central axis 350, and do not overlapwith one another.

The latching ring 368 is positioned inside the latching grooves cage 312and the guiding grooves cage 374, in a space 916 formed between thethird set of teeth 376 of the guiding grooves cage 374 and the fourthset of teeth 378 of the latching grooves cage 312, as shown in FIGS.10B, 11B, and 12B. As shown in FIGS. 10B, 11B, and 12B, the third set ofteeth 376 are shaped to interface with the first set of teeth 370 inonly a single position (e.g., each tooth of the first set of teeth 370fits in a groove formed between adjacent pairs of the third set of teeth376) and the fourth set of teeth 378 are shaped to interface with thesecond set of teeth 372 in two different locking positions (e.g., eachtooth of the fourth set of teeth 378 fit in either the deeper groove 912or the shallower groove 914 formed by the second set of teeth 372). Asshown in FIG. 9A, the guiding grooves cage 374 and latching grooves cage312 couple to one another, at outer walls 924 and 926 via a plurality ofaxially extending tabs 918, spaced apart from one another around acircumference of the guiding grooves cage 374. The third set of teeth376 are formed on an inner wall 930 of the guiding grooves cage 374 andextend in an axial direction, relative to the central axis 350, towardthe latching grooves cage 312 and the fourth set of teeth 378 are formedon an inner wall 928 of the latching grooves cage 312 and extend in theaxial direction toward to guiding grooves cage 374, where the space 916is formed between ends of the third set of teeth 376 and the fourth setof teeth 378.

The latching grooves cage 312 includes a window 920 (e.g., aperture)that aligns with the controller 310 positioned outside of the latchinggrooves cage 312 (relative to the central axis 350), as shown in FIG. 4.As a result, a sensor on the controller may detect the passing magnetassembly 364 arranged on the inner shift fork 362, the inner shift forkarranged within an interior of the latching grooves cage 312 (see FIG.4). Also shown in FIG. 9A, the latching grooves cage 312 includes tabs922 for limiting axial movement (in the negative axial direction, towardthe end of the latching grooves cage 312 including the tabs 922) ofcomponents of the EMPD assembly 200 arranged inside the latching groovescage 312, such as the coil assembly 322 (as shown in FIG. 4).

As explained above, the latching grooves cage 312 and guiding groovescage 374 are both axially and rotationally fixed. Thus, they do notranslate axially along the central axis 350 or relative to one another.However, the latching ring 368 may move axially between the fourth setof teeth 378 and the third set of teeth 376 and the latching ring 368may rotate, around the central axis 350, when moving back and forthbetween the respective teeth of the latching grooves cage 312 and theguiding grooves cage 374. However, the latching ring 368 is nevercoupled to both the third set of teeth 376 and fourth set of teeth 378at once. The movement of the latching ring 368 during shifting of theEMPD assembly 200 is described below with reference to FIGS. 10B, 11B,and 12B.

FIGS. 10B, 11B, and 12B show a cross-sectional view of the latchingsystem 900 described above in the 4×2, 4×4, and EOS positions,respectively. In particular, FIGS. 10B, 11B, and 12B show how thelatching ring 368 is coupled, in different positions, with the latchinggrooves cage 312 in the 4×2 and 4×4 positions and how the latching ringmoves to the guiding grooves cage 374 in the EOS position.

As seen in FIG. 10B, when the EMPD assembly 200 is in the 4×2 position,the deeper grooves 912 of the latching ring 368 and engaged with (e.g.,in mating contact with) and receive the fourth set of teeth 378 of thelatching grooves cage 312. In this position, the latching ring 368 ismoved away from the guiding grooves cage 374 and only coupled with thelatching grooves cage 312. Further, in this position, the latchingsystem 900 maintains the clutch ring in the 4×2 position, even after theelectromagnetic coil is de-energized.

When a command to shift the clutch ring to the 4×4 position is received,the electromagnetic coil of the EMPD assembly 200 is again energized, asdiscussed above, to move the clutch ring into engagement with both thedrive gear and link shaft. As discussed above with reference to FIGS. 3and 4, the latching ring 368 moves axially, together with the clutchring 346 and clutch ring cage. Thus, as the clutch ring moves axially tobe engaged with the drive gear, the latching ring also moves in thepositive axial direction 820 (as shown in FIG. 10B), while the guidinggrooves cage 374 and latching grooves cage 312 remain stationary in theaxial direction. Specifically, the latching ring moves axially, awayfrom the teeth 378 of the latching grooves cage 312 and toward theguiding grooves cage 374. The first set of teeth 370 of the latchingring 368 hit a peak of the third set of teeth 376 and the guidinggrooves cage 374 cause the latching ring 368 to rotate slightly, aroundthe central axis 350, to slide the first set of teeth 370 intoengagement with the grooves of the third set of teeth 376. The slidingmovement of the first set of teeth 370 are depicted by arrow 1102 inFIG. 10B. In this way, the guiding grooves cage 374 index the latchingring 368 one notch (e.g., by one groove of the teeth) in the rotationaldirection around the central axis 350. FIG. 12B shows the EOS positionwhere the first set of teeth 370 of the latching ring 368 are engagedwith the third set of teeth 376 of the guiding grooves cage 374.

In response to reaching the EOS position, the electromagnetic coil maybe de-energized. Upon de-energization of the electromagnetic coil, theclutch ring and latching ring 368 may move in the negative axialdirection 1202 (as shown in FIG. 12B). The latching ring 368 moves inthe negative axial direction 1202 and the higher peaks of the second setof teeth 372, due to their angling and the angling of the fourth set ofteeth 378 of the latching grooves cage 312, slide along the peaks of thefourth set of teeth 378, in the direction shown by arrow 1204 in FIG.12B, so that the shallower grooves 914 are engaged with the peaks of thefourth set of teeth 378, as shown in FIG. 11B. By indexing the latchingring 368 by one notch, such that it rotates by one groove of thelatching ring, in the EOS position, when the latching ring 368 travelsaxially back to the latching grooves cage, the latching ring 368 hasshifted its rotational position relative to the latching grooves cage312, thereby allowing the shallower grooves 914 to be in alignment andengage with the peaks of the fourth set of teeth 378. In this position,the latching system 900 holds the EMPD assembly in the 4×4 position,without the electromagnetic coil having to remain energized.

This process is repeated when transitioning (e.g., shifting) from the4×4 position to the 4×2 position. Specifically, the latching ring 368moves in the positive axial direction 820, as shown in FIG. 11B, fromthe 4×4 position to the EOS position (shown in FIG. 12B). The latchingring 368 again rotates by one notch (or groove) as it slides itengagements with the teeth of the guiding grooves cage 374. Then, whenthe electromagnetic coil is de-energized, the latching ring 368translates back to the latching grooves cage 312 and now the deepergrooves 912 slide into engagement with the teeth 378 of the latchinggrooves cage 312. In this way, the latching ring 368 rotates andadvances one notch, or groove, in one direction, as it alternatesbetween shallower grooves 914 and deeper grooves 912 each time a modeshift is made. Each time a shift is requested from the 4×2 to 4×4position or from the 4×4 position to the 4×2 position, the latchingsystem 900 first shifts to the EOS position in order to rotate thelatching ring 368 and alternate the alignment of the deeper/shallowergrooves with the teeth of the latching grooves cage.

Turning now to FIGS. 10D, 11D, and 12C, views of the magnet assembly 364in the 4×2, 4×4, and EOS shift positions, respectively, are shown. Asdiscussed above, the magnet assembly 364 may be included on an exteriorportion of the inner shift fork 362. FIGS. 10D, 11D, and 12C show themagnet assembly 364, which includes a magnet holder (e.g., sled) 1014coupled to the inner shift fork 362. The magnet assembly 364 includestwo magnets 1008 and 1009 spaced apart from one another and positionedat opposite ends of the magnet holder 1014. Each magnet includes a northpole 1010 and a south pole 1012, where the positioning of the north pole1010 and south pole 1012 portions of each magnet is opposite oneanother. For example, as shown in FIGS. 10D, 11D, and 12C, the leftmost,second magnet 1009 has the south pole 1012 on top (closer to the radialposition of the sensor 1006) while the rightmost, first magnet 1008 hasthe south pole 1012 on bottom (farther from the radial position of thesensor 1006). The magnets 1008 and 1009 are detectable via a sensor 1006arranged on an inner surface, relative to the central axis 350, of thecontroller 310.

The axial position of the magnets 1008 and 1009 of the magnet assembly364 correspond to the axial position of the latching ring 368 and theclutch ring 346 since the inner shift fork 362 moves axially togetherwith the outer shift fork 366, latching ring 368, clutch ring 346, andclutch ring cage 352, as explained above. Thus, the axial position ofthe magnets 1008 and 1009 may correlate to the shift position (4×2, 4×4,or EOS) of the EMPD assembly 200. FIGS. 10A-10D show the EMPD assembly200 in the 4×2 position where the clutch ring is not engaged with thedrive gear, and thus, the clutch ring 346 and latching ring 368 are inthe furthest negative axial position out of all the shift positions(e.g., furthest to the left in FIGS. 10A-10B and closest to the basehousing end of the assembly). As a result, as shown in FIG. 10B, thefirst magnet 1008 is positioned at a same axial position, relative tocentral axis 350 and as depicted by arrow 1016, the sensor 1006, whilethe second magnet 1009 is positioned away from the sensor 1006, in theaxial direction. The sensor 1006 may sense the north pole 1010 of thefirst magnet 1008, and in response, the controller 310 may determine theEMPD assembly 200 is in the 4×2 position.

In contrast, in the 4×4 position, as shown in FIG. 11D, since theassembly has moved in the positive axial direction, as shown by arrow1016, relative to the 4×2 position, the axial position of the sensor1006 is now arranged between the first magnet 1008 and second magnet1009. Thus, the sensor 1006 is not axially aligned with either of themagnets 1008 and 1009. In this position, the sensor 1006 may not detecteither of the magnets 1008 and 1009. In response to this signal from thesensor 1006, the controller 310 determines that the EMPD assembly 200 isin the 4×4 position.

As shown in FIG. 12C, the assembly has moved even further in thepositive axial direction, relative to each of the 4×2 and 4×4 positions,to the EOS position. As a result, the axial position of the sensor 1006is now closer to the second magnet 1009 and positioned away from thefirst magnet 1008. In this position, the sensor 1006 detects the southpole 1012 of the second magnet 1009, and in response, the controller 310may determine the EMPD assembly 200 is in the 4×4 position.

FIGS. 1-12C show example configurations with relative positioning of thevarious components. If shown directly contacting each other, or directlycoupled, then such elements may be referred to as directly contacting ordirectly coupled, respectively, at least in one example. Similarly,elements shown contiguous or adjacent to one another may be contiguousor adjacent to each other, respectively, at least in one example. As anexample, components laying in face-sharing contact with each other maybe referred to as in face-sharing contact. As another example, elementspositioned apart from each other with only a space there-between and noother components may be referred to as such, in at least one example. Asyet another example, elements shown above/below one another, at oppositesides to one another, or to the left/right of one another may bereferred to as such, relative to one another. Further, as shown in thefigures, a topmost element or point of element may be referred to as a“top” of the component and a bottommost element or point of the elementmay be referred to as a “bottom” of the component, in at least oneexample. As used herein, top/bottom, upper/lower, above/below, may berelative to a vertical axis of the figures and used to describepositioning of elements of the figures relative to one another. As such,elements shown above other elements are positioned vertically above theother elements, in one example. As yet another example, shapes of theelements depicted within the figures may be referred to as having thoseshapes (e.g., such as being circular, straight, planar, curved, rounded,chamfered, angled, or the like). Further, elements shown intersectingone another may be referred to as intersecting elements or intersectingone another, in at least one example. Further still, an element shownwithin another element or shown outside of another element may bereferred as such, in one example.

FIGS. 13A-13B depict a method 1300 for operating the EMPD assembly 200discussed above. It is noted that the various steps and decision-makingprocesses may be stored in the memory of a main vehicle controllerexternal to the EMPD assembly 200. In other examples, a localized hubcontroller may be coupled directly to EMPD assembly 200 and execute thesteps of method 1300 while communicating with the external, main vehiclecontroller. In yet another example, the various steps anddecision-making processes of method 1300 may be stored in a memory ofthe EMPD assembly controller (such as controller 310 shown in FIGS. 3,4, 10D, 11D, and 12C). As such, the EMPD assembly controller may executemethod 1300 in combination with the various sensors (e.g., positionsensor 1006) and actuators (e.g., contact assembly coil electromagneticcoil assembly 322) of the EMPD assembly. To reiterate, the 4×2 (2WD) orfirst mode corresponds to the first position where clutch ring 346engages only one rotating component (e.g., link shaft 208) while the 4×4(4WD) or second mode corresponds to the second position where clutchring 346 engages both rotating components (e.g., the link shaft 208 anddrive gear 358 coupled with another shaft or axle), thereby coupling thetwo rotating components together. Lastly, the end-of-shift (EOS)position corresponds to where the clutch ring 346 and other attachedcomponents are farthest shifted in the axial direction when theelectromagnetic coil 502 is energized. This can be seen FIGS. 12A-12C,where the EOS position is the rightmost position compared to the 4×2 and4×4 positions. For ease of understanding, reference will be made tocomponents and description presented with regards to the previousfigures. However, method 1300 may be employed in alternate EMPDassemblies having different configurations than described above.

First, referring to FIG. 13A, at 1301 the method includes performing aseries of initialization operations. The initialization operations mayinclude calibrating the position sensor (e.g., position sensor 1006) somagnetic force (e.g., sensing north pole, smaller magnetic force ormagnetic forces of both magnets, or south pole) of the magnet assemblymay be correlated to the 4×2, 4×4, or EOS positions, determiningdirection of travel of the vehicle, and synchronizing the rotationalspeed of the two rotating components (e.g., the two rotating componentsthat may be selectively and rotatably coupled via the clutch ring of thedisconnect). Next, at 1302, an operator (i.e. driver) or other systemmay be send an input command to the controller or similar device. Theinput command may be a request to shift from the 4×4 mode to the 4×2mode or vice versa. As such, the method at 1302 may include receivingand reading the input command from the controller. Upon receiving theshift command, at 1303 the method includes determining which shift modehas been commanded (i.e. requested) by the vehicle operator. If 4×2operation is requested, then the method continues at 1313 in FIG. 13B.Alternatively, if 4×4 operation is requested, then the method continuesat 1304 in FIG. 13A.

At 1304, the method includes determining if the EMPD assembly 200 is inthe 4×4 (second) position, that is, when clutch ring 346 along with theother components that translate axially with clutch ring 346 are in the4×4 position, thereby coupling the two rotating components together. Atstep 1304 and the other steps of method 1300 where it is determinedwhether the EMPD assembly 200 is in a certain position (e.g., 4×4, 4×2,or EOS), the controller may determine this based on an output of aposition sensor (e.g., position sensor 1006), as described above withreference to FIGS. 10D, 11D, and 12C. If the EMPD assembly 200 isalready in the 4×4 position, then at 1312 the method includes outputtinga 4×4 feedback signal to the external vehicle controller to notify theoperator and other system of the current 4×4 position. Alternatively, ifat 1304 the EMPD assembly 200 is not the 4×4 position, then at 1305 anelectrical current may be sent to energize the electromagnetic coil ofcoil assembly 322. As previously explained, with energizing the coil ofcoil assembly 322, the clutch and latching ring assemblies may move inthe positive axial direction. Next, at 1306, the sensor 1006 may detectif EMPD assembly 200 is at the EOS position, as discussed above. Thecontroller may determine the EMPD assembly 200 is in the EOS position inresponse to the sensor 1006 detecting a south pole magnetic force (fromsecond magnet 1009). If the EMPD assembly 200 has not yet reached theEOS position, then at 1307 a timer or other device may determine if amaximum allowable time for energizing the coil of the coil assembly 322has passed. In one example, the maximum allowable time for pulsing thecoil of the coil assembly 322 may aid in reducing degradation of thecoil 502 and armature cam 328. If the maximum allowable time has notexpired, then the method at 1306 may be repeated to continually check ifthe EMPD assembly 200 has reached the EOS position. Conversely, if themaximum allowable time has expired, then at 1308 current may stopflowing to coil of the coil assembly 322, thereby de-energizing the coil502. Furthermore, a cooling period may be initiated to allow the coil502 to cool off before proceeding back to 1306.

At 1306, once the EOS position has been reached, then at 1309 the coil502 of coil assembly 322 may be de-energized. Upon de-energizing thecoil 502, the clutch and latching ring assemblies move axially towardsthe 4×4 position and corresponding latching grooves. While this motionis occurring, at 1310 the sensor 1006 may monitor the position of theEMPD assembly 200. In one example, the sensor 1006 may continuouslyoutput a signal corresponding to the magnetic force detected by thesensor 1006. At 1311, the method includes determining if the EMPDassembly 200 is in the 4×4 position. If the 4×4 position has not yetbeen reached, then the process continues to 1322 to determine of athreshold (e.g., maximum) number of shift attempts has been exceeded. Ifthe threshold number of shift attempts has been exceeded, the processends. Since method 1300 may repeat continuously, the method may restartat 1302 instead of 1301 during a single drive cycle. If the thresholdnumber of shift attempts has not been exceeded, the method loops back to1304 to determine if the EMPD is in the 4×4 position. Conversely at1311, if the controller 310, via the output signal of sensor 1006,determines that the EMPD assembly 200 is in the 4×4 position, then at1312 the method includes outputting a 4×4 feedback signal to the vehiclecontroller and/or vehicle operator, thereby ending method 1300.

At 1303, if 4×2 operation is requested, then method 1300 proceeds inFIG. 13B. The methods at 813-823 of FIG. 13B may be similar to methods804-812 of FIG. 13A, while FIG. 13B focuses on shifting to the 4×2position. As such, for the sake of brevity, brief descriptions of eachof the methods at 813-821 will be presented while the description abovefor FIG. 13A may be referenced for more thorough descriptions. Referringto FIG. 13A, at 1313 the method includes determining if EMPD assembly200 is in the 4×2 position. If the 4×2 position has been reached, thenthe method may end at 1321 by outputting a 4×2 feedback signal to thevehicle controller. Alternatively, at 1314 the electromagnetic coil ofcoil assembly 322 may be energized if the EMPD assembly 200 is not the4×2 position. At 1315, if the EMPD 200 is not at the EOS position, thenthe methods at 1316 and/or 1317 may be initiated to allow EMPD 200 toreach the EOS position without overheating the coil 502 by allowingcooling of the coil and adhering to the maximum allowable pulse time.Once the EMPD 200 is at the EOS position, then at 1318 the coil 220 maybe de-energized to allow the EMPD 200 to translate in the opposite,negative axial direction. The position of EMPD 200 may be monitored bythe sensor 1006 at 1319 until the method determines if EMPD 200 hasreached the requested 4×2 position at 1320. If EMPD 200 has not reachedthe 4×2 position, then several of the methods of FIG. 13B may berepeated after determining whether or not the threshold number of shiftattempts has been reached at 1323. Alternatively, if the 4×2 positionhas been reached, then at 1321 the 4×2 feedback signal may be outputtedto the vehicle controller, thereby ending method 1300.

In this way, the EMPD assembly 200 may provide selective engagementbetween two rotating components while reducing electrical powerconsumption and not relying on vacuum as a power source. Since thelatching system including the latching ring, latching grooves cage, andguiding grooves cage may hold the EMPD assembly 200 in the 4×4 and 4×2positions, electrical current may only be provided when shifting betweenthe 4×2 and 4×4 positions. Therefore, EMPD assembly 200 may conservepower where other disconnect assemblies may be provided with acontinuous current. Furthermore, the floating aspect of the coilassembly 322 (e.g., movable slightly in the axial direction) asdescribed above may increase the durability and longevity of the coilassembly 322 and armature cam 328. Additionally, the friction diskprovided on the surface of the coil assembly 322 that is adapted to haveface-sharing contact with the armature cam 328 when the electromagneticcoil is energized may further reduce wear between the coil assembly andarmature cam.

Further still, the shape and arrangement of components of the EMPDassembly 200 may work together to make a more compact EMPD assembly,thereby increasing the flexibility of the assembly in differentvehicles, drivetrain locations, and other applications. For example, thearmature cam with the axially extending bidirectional ramps whichinterface with the radially extending guides and elongate apertures ofthe cam follower allow these components to nest together and reduce anaxial length of the assembly, making the overall assembly more compact.Additionally, the combination of the interfacing teeth of the latchinggrooves cage, guiding grooves cage, and latching ring further increasethe compact nature of the EMPD assembly.

In one embodiment, an electromagnetic disconnect assembly (e.g., anelectromagnetic pulse disconnect assembly) includes: an electromagneticcoil assembly including an electromagnetic coil arranged within anannular housing of the coil assembly, where a first end of the annularhousing includes a first face; an armature cam including an annular ringwith an outer face and an inner face, a plurality of bidirectional camramps extending in an axial direction from the inner face, where theouter face is adapted to have face-sharing contact with the first faceof the electromagnetic coil assembly when the electromagnetic coil isenergized and be spaced apart from the first face via an air gap whenthe electromagnetic coil is de-energized; and a cam follower includingan outer annular ring and an inner annular ring coupled together via aplurality of radially extending guides arranged around a circumferenceof the cam follower, the plurality of radially extending guides spacedapart from one another via a plurality of elongate apertures, each ofthe plurality of elongate apertures adapted to receive one of theplurality of bidirectional ramps of the armature cam. In a first exampleof the assembly, the first face is annular and includes a frictionmaterial arranged in a ring around an entirety of the first face, thefriction material adapted to have face-sharing contact with the outerface of the armature cam when the electromagnetic coil is energized. Asecond example of the assembly optionally includes the first example andfurther includes, wherein a length of each of the plurality of elongateapertures, in a direction of a circumference of the inner and outerannular rings, is longer than a length of each of the plurality ofradially extending guides, in the direction of the circumference of theinner and outer annular rings. A third example of the assemblyoptionally includes one or more of the first and second examples andfurther includes, wherein a planar connecting platform arranged inparallel with and coupled to the inner face separates each bidirectionalcam ramp from adjacent bidirectional cam ramps of the plurality ofbidirectional camp ramps and wherein each bidirectional cam rampincludes a first ramp and a second ramp that meet at an apex of thebidirectional camp ramp, the apex positioned away from the inner face ofthe annular ring of the armature cam, the first ramp extending outwardfrom a first connecting platform to the apex and the second rampextending outward from a different, second connecting platform to theapex, the first and second connecting platforms spaced apart from oneanother. A fourth example of the assembly optionally includes one ormore of the first through third examples and further includes, whereinthe length of each of the plurality of radially extending guides is thesame as a length of each connecting platform and wherein each of theplurality of elongate apertures are shaped to fit around an entirety ofa corresponding bidirectional ramp of the plurality of bidirectionalramps when the electromagnetic coil is de-energized. A fifth example ofthe assembly optionally includes one or more of the first through fourthexamples and further includes, wherein the annular housing includes asecond end, the second end having a second face arranged opposite to thefirst face, the second face having an annular slot depressed inward intothe second face. A sixth example of the assembly optionally includes oneor more of the first through fifth examples and further includes anannular spacer adapted to fit within the annular slot, the annularspacer coupled with a housing of the electromagnetic disconnectassembly, the electromagnetic coil assembly, annular spacer, armaturecam, and cam follower all arranged within an interior of the housing ofthe electromagnetic disconnect assembly. A seventh example of theassembly optionally includes one or more of the first through sixthexamples and further includes, wherein the electromagnetic coil assemblyfurther includes four coil springs arranged around the annular housingan extending axially across the annular housing, where only two of thefour coil springs are electrically coupled to the electromagnetic coil.An eighth example of the assembly optionally includes one or more of thefirst through seventh examples and further includes, wherein each of thefirst face, inner face, and outer face are arranged parallel to oneanother and normal to a central axis of the electromagnetic disconnectassembly and wherein the radially extending guides extend radiallybetween the outer annular ring and inner annular ring relative to thecentral axis. A ninth example of the assembly optionally includes one ormore of the first through eighth examples and further includes, whereinthe inner annular ring of the cam follower includes a plurality of teetharranged around a circumference of an inner surface of the inner annularring and further comprising clutch ring adapted to translate axiallybetween an engaged position where the clutch ring couples two rotatingcomponents to one another and a disengaged position where the clutchring is only coupled to one of the two rotating components, where thecam follower is arranged adjacent to the clutch ring and the clutch ringis adapted to move axially with axial movement of the cam follower. Atenth example of the assembly optionally includes one or more of thefirst through ninth examples and further includes a latching systemincluding a latching ring positioned between a stationary latchinggrooves cage and stationary guiding grooves cages coupled to oneanother, the latching ring adapted to translate axially within a spaceformed within the coupled together latching grooves cage and guidinggrooves cage, the latching ring surrounding a clutch ring cage housingthe clutch ring and adapted to translate axially along with the clutchring.

In another embodiment, an electromagnetic disconnect assembly (e.g., anelectromagnetic pulse disconnect assembly) includes: an electromagneticcoil assembly; a clutch ring; and a latching system adapted to hold theclutch ring in a first, engaged position where the clutch ring connectstwo rotating components or a second, disengaged position where theclutch ring is only connected to one of the two rotating components,after energizing the electromagnetic coil assembly to move the clutchring into either the first or second position and after de-energizingthe electromagnetic coil assembly, the latching system comprising: anannular, latching ring including a first set of teeth arranged on afirst side of the latching ring and having a first profile with asingle, same-depth tooth pattern that repeats around a circumference ofthe latching ring and a second set of teeth arranged on an opposite,second side of the latching ring and having a second profile with adifferent-depth tooth pattern having two different depths that repeatsaround the circumference of the latching ring; a guiding grooves cageincluding a third set of teeth adapted to interface with the first setof teeth in a single position; and a latching grooves cage including afourth set of teeth adapted to interface with the second set of teeth intwo different locking positions. In a first example of the assembly, thesecond profile of the second set of teeth includes a deeper groove and ashallower groove which repeat continuously around the circumference ofthe latching ring. A second example of the assembly optionally includesthe first example and further includes, wherein when the clutch ring isin the first position each tooth of the fourth set of teeth ispositioned within one shallower groove of the second set of teeth andwherein when the clutch ring is in the second position each tooth of thefourth set of teeth is position within one deeper groove of the secondset of teeth. A third example of the assembly optionally includes one ormore of the first and second examples and further includes, wherein theguiding grooves cage and the latching grooves cage are rotationally andaxially fixed, relative to a central axis of the electromagneticdisconnect assembly, and wherein the guiding grooves cage and latchinggrooves cage are coupled to one another at outer walls of the guidinggrooves cage and latching grooves cage. A fourth example of the assemblyoptionally includes one or more of the first through third examples andfurther includes, wherein the third set of teeth are formed on an innerwall of the guiding grooves cage and extend in an axial direction,relative to the central axis, toward the latching grooves cage andwherein the fourth set of teeth are formed on an inner wall of thelatching grooves cage and extend in the axial direction toward toguiding grooves cage, where a space is formed between ends of the thirdset of teeth and the fourth set of teeth. A fifth example of theassembly optionally includes one or more of the first through fourthexamples and further includes, wherein the latching ring is positionedwithin the space and is free to rotate and translate axially, betweenthe third set of teeth and fourth set of teeth. A sixth example of theassembly optionally includes one or more of the first through fifthexamples and further includes an armature cam including a plurality ofbidirectional ramps extending axially from an annular ring and a camfollower including a plurality of radially extending guides spaced apartfrom one another via a plurality of elongate apertures, the plurality ofbidirectional ramps adapted to fit within the plurality of elongateapertures and wherein the armature cam is adapted to have face sharingcontact with the electromagnetic coil assembly when the electromagneticcoil assembly is energized.

In yet another embodiment, a method (e.g., a method for anelectromagnetic pulse disconnect assembly) includes: in response to eachof a first command to shift a clutch ring of an electromagnetic pulsedisconnect (EMPD) assembly from a first position, where two rotatingcomponents are coupled together via the clutch ring, to a secondposition, where the two rotating components are not coupled together viathe clutch ring, and a second command to shift the clutch ring from thesecond position to the first position, energizing an electromagneticcoil of an electromagnetic coil assembly in the EMPD assembly; inresponse to sensing via a sensor on a controller arranged outside of alatching grooves cage of the EMPD assembly that the EMPD assembly is inan end-of-shift position, de-energizing the electromagnetic coil, theend-of-shift position defined by the clutch ring being coupled to eachof the two rotating components and a first set of teeth of a latchingring being engaged with a second set of teeth of a guiding grooves cagecoupled to the latching grooves cage, where the first set of teeth aredefined by a single-depth repeating groove around an entirecircumference of the latching ring, the latching ring further includinga third set of teeth defined by a deeper groove and shallower groovethat repeat around the entire circumference of the latching ring, thethird set of teeth adapted to interface in two different positions witha fourth set of teeth of the latching grooves cage, the latching ringsurrounding a clutch ring cage housing the clutch ring and adapted totranslate axially together with the clutch ring in a space createdinside the coupled together latching grooves cage and guiding groovescage; and after de-energizing the electromagnetic coil, sensing via thesensor that the clutch ring is in the commanded first position or secondposition, where in each of the first position and the second positionthe third set of teeth of the latching ring is engaged with the fourthset of teeth of the latching grooves cage and positioned axially awayfrom the second set of teeth of the guiding grooves cage. In a firstexample of the method, sensing via the sensor includes sensing an axialposition, relative to a central rotational axis of the EMPD assembly, ofa magnet assembly arranged on a shift fork of the EMPD assembly, thelatching ring surrounding the shift fork and the shift fork adapted tomove axially together with the latching ring and clutch ring.

In another representation, a method of operating a disconnect assemblyof a shaft, comprises: driving a clutch ring and a latching system ofthe disconnect assembly from a first self-locking position to a secondself-locking position via an electromagnetic coil generating an axialforce through an armature cam and cam follower assembly, the armaturecam including a series of bi-directional ramps interfacing with radiallyextending guides of the cam follower, the guides positioned around acircumference of the cam follower and spaced apart from one another viaelongate apertures adapted to receive the series of bidirectional ramps,the coil energized only during transitions between the first and secondself-locking positions, the first and second self-locking positionsincluding a shaft engaging position and a shaft disengaging position;activating and then deactivating the coil to transition the clutch ringand latching system from the first self-locking position to the secondself-locking position and activating and deactivating the coil totransition the clutch ring and latching system from the secondself-locking position to the first self-locking position; andmaintaining the clutch ring and latching system in the firstself-locking position or the second self-locking position when the coilis deactivated, even when transmitting and not transmitting torque androtation of the shaft through the disconnect assembly. In a firstexample of the method, the clutch ring includes a plurality of teeth forselectively engaging the shaft, the clutch ring coupled with thelatching system and wherein driving the clutch ring and latching systemincludes translating the clutch ring and a latching ring of the latchingsystem positioned adjacent to the cam follower axially together, in adirection of a central axis of the disconnect assembly, between thefirst and second self-locking positions while the clutch ring and thelatching ring rotate independent of each other. A second example of themethod optionally includes the first example and further includessensing the first and second self-locking positions via a sensorarranged on a controller of the disconnect assembly, where the sensingincludes sensing a magnet assembly arranged on a shift fork that movesaxially together with the latching ring and clutch ring.

In yet another representation, an electromagnetic disconnect assembly(e.g., an electromagnetic pulse disconnect assembly) comprises anelectromagnetic coil assembly including an electromagnetic coil arrangedwithin an annular housing of the coil assembly; an armature camincluding an annular ring and a plurality of bidirectional cam rampsextending in an axial direction from the annular ring, where the annularring is adapted to have face-sharing contact with the electromagneticcoil assembly when the electromagnetic coil is energized and be spacedapart from the electromagnetic coil assembly when the electromagneticcoil is de-energized; and a cam follower including a plurality ofradially extending guides arranged around a circumference of the camfollower, the plurality of radially extending guides spaced apart fromone another via a plurality of elongate apertures, each of the pluralityof elongate apertures adapted to receive one of the plurality ofbidirectional ramps of the armature cam. In a first example of theassembly, the assembly further comprises a clutch ring and a latchingsystem adapted to hold the clutch ring in a first, engaged positionwhere the clutch ring connects two rotating components or a second,disengaged position where the clutch ring is only connected to one ofthe two rotating components, after energizing the electromagnetic coilassembly to move the clutch ring into either the first or secondposition and after de-energizing the electromagnetic coil assembly, thelatching system comprising: an annular latching ring positioned in aspace created by outer wall of a guiding grooves cage and a latchinggrooves cage of the latching system, the guiding grooves cage coupled tothe latching grooves cage via the outer walls. A second example of theassembly optionally includes the first example and further includeswherein the latching ring includes a first set of teeth arranged on afirst side of the latching ring and having a first profile with asingle, same-depth tooth pattern that repeats around a circumference ofthe latching ring and a second set of teeth arranged on an opposite,second side of the latching ring and having a second profile with adifferent-depth tooth pattern having two different depths that repeatsaround the circumference of the latching ring. A third example of theassembly optionally includes one or more of the first and secondexamples and further includes wherein the guiding grooves cage includesa third set of teeth adapted to interface with the first set of teeth ina single position and wherein the latching grooves cage includes afourth set of teeth adapted to interface with the second set of teeth intwo different locking positions.

In still another representation, an electromagnetic disconnect assembly(e.g., an electromagnetic pulse disconnect assembly) comprises a clutchring adapted to selectively connect and disconnect two rotatingcomponents, an electromagnetic coil assembly, a cam follower adapted torotate along with one of the two rotating components via a plurality ofteeth arranged around an inner surface of the cam follower, an armaturecam adapted to rotate along with the cam follower when theelectromagnetic coil assembly is de-energized and stop rotating with thecam follower when the electromagnetic coil assembly is energized, and alatching system adapted to hold the clutch ring in selective connectionand disconnection with the two rotating components, even when theelectromagnetic coil assembly is de-energized, a latching ring of thelatching system adapted to translate axially with the cam follower, thecam follower adapted to move axially away from the armature cam when theelectromagnetic coil assembly is energized.

The control methods and routines disclosed herein may be stored asexecutable instructions in non-transitory memory and may be carried outby the control system including the controller in combination with thevarious sensors, actuators, and other engine hardware. The specificroutines described herein may represent one or more of any number ofprocessing strategies such as event-driven, interrupt-driven,multi-tasking, multi-threading, and the like. As such, various actions,operations, and/or functions illustrated may be performed in thesequence illustrated, in parallel, or in some cases omitted. Likewise,the order of processing is not necessarily required to achieve thefeatures and advantages of the example embodiments described herein, butis provided for ease of illustration and description. One or more of theillustrated actions, operations and/or functions may be repeatedlyperformed depending on the particular strategy being used. Further, thedescribed actions, operations and/or functions may graphically representcode to be programmed into non-transitory memory of the computerreadable storage medium in the engine control system, where thedescribed actions are carried out by executing the instructions in asystem including the various engine hardware components in combinationwith the electronic controller.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. The subject matter of the present disclosure includes allnovel and non-obvious combinations and sub-combinations of the varioussystems and configurations, and other features, functions, and/orproperties disclosed herein.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

1-18. (canceled)
 19. A method, comprising: in response to each of afirst command to shift a clutch ring of an electromagnetic pulsedisconnect (EMPD) assembly from a first position, where two rotatingcomponents are coupled together via the clutch ring, to a secondposition, where the two rotating components are not coupled together viathe clutch ring, and a second command to shift the clutch ring from thesecond position to the first position, energizing an electromagneticcoil of an electromagnetic coil assembly in the EMPD assembly; inresponse to sensing via a sensor on a controller arranged outside of alatching grooves cage of the EMPD assembly that the EMPD assembly is inan end-of-shift position, de-energizing the electromagnetic coil, theend-of-shift position defined by the clutch ring being coupled to eachof the two rotating components and a first set of teeth of a latchingring being engaged with a second set of teeth of a guiding grooves cagecoupled to the latching grooves cage, where the first set of teeth aredefined by a single-depth repeating groove around an entirecircumference of the latching ring, the latching ring further includinga third set of teeth defined by a deeper groove and shallower groovethat repeat around the entire circumference of the latching ring, thethird set of teeth adapted to interface in two different positions witha fourth set of teeth of the latching grooves cage, the latching ringsurrounding a clutch ring cage housing the clutch ring and adapted totranslate axially together with the clutch ring in a space createdinside the coupled together latching grooves cage and guiding groovescage; and after de-energizing the electromagnetic coil, sensing via thesensor that the clutch ring is in the commanded first position or secondposition, where in each of the first position and the second positionthe third set of teeth of the latching ring is engaged with the fourthset of teeth of the latching grooves cage and positioned axially awayfrom the second set of teeth of the guiding grooves cage.
 20. The methodof claim 19, wherein sensing via the sensor includes sensing an axialposition, relative to a central rotational axis of the EMPD assembly, ofa magnet assembly arranged on a shift fork of the EMPD assembly, thelatching ring surrounding the shift fork and the shift fork adapted tomove axially together with the latching ring and clutch ring.
 21. Themethod of claim 19, wherein a profile of the second set of teethincludes a deeper groove and a shallower groove which repeatcontinuously around the circumference of the latching ring.
 22. Themethod of claim 21, wherein when the clutch ring is in the firstposition each tooth of the fourth set of teeth is positioned within oneshallower groove of the second set of teeth and wherein when the clutchring is in the second position each tooth of the fourth set of teeth isposition within one deeper groove of the second set of teeth.
 23. Themethod of claim 19, wherein the guiding grooves cage and the latchinggrooves cage are rotationally and axially fixed, relative to a centralaxis of the EMPD assembly, and wherein the guiding grooves cage andlatching grooves cage are coupled to one another at outer walls of theguiding grooves cage and latching grooves cage.
 24. The method of claim23, wherein the third set of teeth are formed on an inner wall of theguiding grooves cage and extend in an axial direction, relative to thecentral axis, toward the latching grooves cage and wherein the fourthset of teeth are formed on an inner wall of the latching grooves cageand extend in the axial direction toward to guiding grooves cage, wherea space is formed between ends of the third set of teeth and the fourthset of teeth.
 25. The method of claim 24, wherein the latching ring ispositioned within the space between ends of the third set of teeth andthe fourth set of teeth and rotates and translates axially, between thethird set of teeth and fourth set of teeth.
 26. The method of claim 19,further comprising de-energizing the EMPD assembly for a cooling periodin response to a maximum time of energization.
 27. The method of claim19, further determining if a maximum amount of shift attempts has beenexceeded, and if exceeded, then ending the attempted shifts.